Problem: $-9lm + 3m - 8n - 8 = 5m - 2n + 8$ Solve for $l$.
Solution: Combine constant terms on the right. $-9lm + 3m - 8n - {8} = 5m - 2n + {8}$ $-9lm + 3m - 8n = 5m - 2n + {16}$ Combine $n$ terms on the right. $-9lm + 3m - {8n} = 5m - {2n} + 16$ $-9lm + 3m = 5m + {6n} + 16$ Combine $m$ terms on the right. $-9lm + {3m} = {5m} + 6n + 16$ $-9lm = {2m} + 6n + 16$ Isolate $l$ $-{9}l{m} = 2m + 6n + 16$ $l = \dfrac{ 2m + 6n + 16 }{ -{9m} }$ Swap the signs so the denominator isn't negative. $l = \dfrac{ -{2}m - {6}n - {16} }{ {9m} }$